Gaseous electric discharge lamp device



Dec. 3', 1940. I

P. M. VAN ALPHEN ET AL GASEOUS ELECTRIC DISCHARGE LAMP DEVICE Film ad Nov. 16, 1937 2 Sheets-Sheet 1 I n 5 MN l m Amfi s m Y mw flm T 656 NM u T w b rr ,A m y .md PEHB De 3, 19 0- P. M. VAN ALPHEN arm. 2,223,470

GASEOUS ELECTRIC DISCHARGE LAME DEVICE Filed Nov. 16, 1937 2 Sheets-Shet 2 Fig. 3

INVENTORS I Pieter M.va.n Alphe Eduard G. Dorgelo lla'iYemir'icus J. Lem. ens X (5/7 AT ORNEY the tube 55 into the apparatus and passes out of the tubes l8 and Il.

The lamp devices 2 and 3 have thereinbetween a glass plate l8 having a thickness of about 1.5

mm. and which supports the arched glass platel9 which has a like thickness and which is inter--' posed between the lamp device I on one hand and the lamp devices 2 and 3 on the other hand. The glass plates is and I9 consist of a glass having the following composition:

About 0.5% of lead chromate is added to the glass batch. This glass composition is a yellow glass which cuts oil the ultra-violet rays and the short wave-length visible rays, such as the violet and blue rays emitted by the discharge lamp devices. At a thickness of 1.5 mm. the glass absorbs about of the rays having a wave-length of 4100 5., about 74% of the rays having a wave-length of 4200 A., and about 57% of the rays having a wavelength of about 4400 A.

The embodiment shown in Figs. 3 and 4 of the drawings comprises a high pressure lamp device 20 of the type which is not liquid cooled and which comprises a tubular container of vitreous material, such as quartz, having an internal diameter of about 5 mm. and an external diameter of about 7.5 mm. A pair of activated, thermionic electrodes is mounted in said container, one at each end thereof, and said container has a quantity of mercury therein in such amount that it is completely vaporized when the lamp is at operating equilibrium. \Vhen desired, a larger quantity of mercury is used. A starting gas, such as argon, is present in said container 29. The lamp device illustrated in Figs. 3 and 4 is operated at lower currents than the lamp device illustrated in Figs. 1 and 2 and a current load thereon of about 35 watts per cm. of the length of the discharge path is preferred. The mercury vapor pressure is then about 20 atmospheres. The lamp device 2% is mounted in an evacuated bulb 2| of vitreous material, such as a glass or quartz bulb and is supported in said bulb 2! by the current leads 22 and 23 connected to the electrode leads of the lamp device 20. Said leads 22 and 23 are sealed into the press 24 of the bulb 2|. When desired, the bulb 2! is provided with an inert gaseous filling, such as nitrogen. A reflector is mounted in said bulb 2| in a parallel position with said lamp device 20 to direct the light from said lamp device 20 in a desired direction. Said reflector consists of an arched glass plate 25 having a reflecting metal coating 25 on the surface there of remote from the lamp device 20. The glass plate 26 is cylindrical in shape so that the reflecting metal coating 25 thereon is in the form of a cylinder, the axis of which coincides with the longitudinal axis of the lamp device 20'.

Preferably the glass plate 26 consists of a glass The lamp devices described above are highly efficient ones having a long'useful operating life.

What we claim as new and desire to secure by Letters Patent of the United States is:

l. A lamp unit comprising in combination a gaseous electric discharge device of the high vapor pressure type capable of emitting visible and ultra violet rays, another source of similar rays associated with said lamp device in such manner that the rays from said source are incident on said lamp device and a filter interposed between said lamp device and said source for absorbing ultraviolet rays to lengthen the useful operating life of said lamp device.

2. A lamp unit comprising in combination agaseous electric discharge device of the high vapor pressure type capable of emitting visible and ultra violet rays, another source ofsimilar rays associated with said lamp device in such manner that the rays from said source are incident on said lamp device and a filter interposed between said lamp device and said source for absorbing rays of a wave-length shorter than 4500 A. to increase the useful life of said lamp device.

3. A lamp unit comprising in combination a gaseous electric discharge device of the high vapor pressure type capable of emitting visible and ultra violet rays, another source of similar rays associated with said lamp device in such manner that the rays from said source are incident on said lamp device and a filter of colored glass interposed between said lamp device and said source for absorbing blue, violet and ultraviolet rays to lengthenthe useful operating life of said lamp device.

4. A lamp unit comprising in combination a gaseous electric discharge device of the high vapor pressure type capable of emitting visible and ultra violet rays, a reflector associated with said lamp device and a filter interposed between-said lamp device and said reflector for absorbing the rays of shorter wave-length emitted by said lamp device to lengthen the useful operating life of said lamp device.

5. A lamp unit comprising in combination a gaseous electric discharge device of the high vapor pressure type capable of emitting visible and ultra violet rays, another gaseous electric discharge device of the same type capable of emitting similar rays, said devices being mounted in such position relative to each other that the rays from each device are incident on the other of said devices and a filter interposed between said devices for absorbing ultraviolet rays emitted by each of said devices in the direction of the other of said devices to lengthen the useful operating life of said devices.

6. A lamp unit comprising in combination, a' gaseous electric discharge device of the high vapor pressure type capable of emitting visible and ultraviolet rays, a radiation projecting means mounted in light receiving relation to said discharge device, said means being capable of projecting visible and ultraviolet rays toward said discharge device and a filter interposed between said device and said projecting means for absorbing ultraviolet rays to lengthen the useful operating life of said device. 1

PIET'ER M. VAN ALPHEN. EDUARD G. DORGELO. HENDRICUS J. LEMMENS. 

